Warm ocean water main culprit behind melting ice shelf

Washington: Researchers have said that warm ocean water, and not warm air, is melting the Pine Island Glacier`s floating ice shelf in Antarctica and could be blamed for increased melting of other ice shelves.

Sridhar Anandakrishnan, professor of geosciences, Pennsylvania State University, said that they`ve been dumping heat into the atmosphere for years and the oceans have been doing their job, taking it out of the air and into the ocean.

He said that eventually, with all that atmospheric heat, the oceans will heat up.

The researchers looked at the remote Pine Island Glacier, a major outlet of the West Antarctic Ice Sheet, as it has rapidly thinned and accelerated in the recent past.

Pine Island Glacier or PIG lies far from McMurdo base, the usual location of American research in Antarctica.

The ice shelf is melting more rapidly from below for a number of reasons.

The oceans are warmer than they have been in the past and water can transfer more heat than air. More importantly, the terrain beneath the ice shelf is a series of channels. The floating ice in the channel has ample room beneath it for ocean water to flow in.

The water melts some of the ice beneath and cools. If the water remained in the channel, the water would eventually cool to a point where it was not melting much ice, but the channels allow the water to flow out to the open ocean and warmer water to flow in, again melting the ice shelf from beneath.

The researchers believe that the interaction of the ocean beneath the ice shelf and melting of the ice shelf is an important variable that should be incorporated into the sea level rise models of global warming.